Oral bioaccessibility of potentially toxic elements (PTEs) and related health risk in urban playground soil from a medieval bell metal industrial town Khagra, India

In vitro oral bioaccessibility assay (simple bioaccessibility extraction test) was used to assess bioaccessible PTEs (As, Cd, Co, Cu, Fe, Mn, Ni, Pb, Sn, and Zn) in 16 playground soils of Khagra, which is a medieval bell metal industrial town at Murshidabad district, West Bengal, India. The aim was also to establish levels of potentially toxic elements (PTEs) in soil, their origin, and human health risk, particularly on children. The average pseudo-total PTEs content in playground soil samples was in the decreasing order of Fe (18,988 mg kg(-1)) > Zn (1229 mg kg(-1)) > Cu (999 mg kg(-1)) > Mn (343 mg kg(-1)) > Pb (181 mg kg(-1)) > Sn (132 mg kg(-1)) > Co (8.63 mg kg(-1)) > As (5.21 mg kg(-1)) > Cd (0.88 mg kg(-1)). The pollution indices indicate significant enrichment of Cd, Cu, Pb, Zn, and Sn in the playground. The bioaccessible percentage of PTEs in the 16 playground soils ranged from 0 to 80.25%, where the range of percentage of bioaccessibility was 13.24-62.50, 0-61.46, 16.82-28.79, 5.05-73.06, 0.96-6.14, 2.28-38, and 0-80 for As, Cd, Co, Cu, Fe, Ni, and Zn, respectively. The order of percentage of bioaccessibility was As > Mn > Zn > Sn > Cu > Co > Pb > Cd > Ni > Fe. PCA extracted two major factors indicating the anthropogenic (Cd, Cu, Ni, Pb, Zn, and Sn) and geogenic (Co, Fe, and Mn) source. Stepwise multiple regression analysis exhibited that the oral bioaccessibility of PTEs did not correlate with physicochemical parameters like pH, EC. In contrast, Sn had a significant correlation with that of organic matter. The health risk for pseudo-total as well as bioavailable fraction in playground soil depicted that children were more vulnerable to ingestion of soil contaminated with PTEs, particularly for Cu and Pb. A risk management plan with the bioaccessible data involving detailed site-specific exposure factors to indicate the importance of the study in terms of child health safety is required.